1. Field of the Invention
The present invention relates to an in vivo information acquiring apparatus that is introduced to an inner portion of a subject and acquires information on an inside of a living body.
2. Description of the Related Art
In recent years, in the field of endoscopes, in vivo information acquiring apparatuses, which are swallow-type capsule endoscopes, have appeared. A capsule endoscope, which is swallowed from the mouth of a subject and thereby introduced to the inside of the body, has a function of moving inside body cavities, for example, organs such as the stomach and the small intestine according to peristaltic motion to sequentially pick up images until the capsule endoscope is naturally egested.
During the movement inside the body cavities, data of images picked up by the capsule endoscope inside the body is transmitted to the outside via wireless communication and accumulated in a memory provided inside an external receiver. After a patient swallows a capsule endoscope, the patient is free to do what he/she wants until the capsule endoscope is egested, carrying a receiver having the wireless communication function and the memory function with him/her.
A capsule endoscope obtains drive power from, e.g., a battery incorporated in its casing; however, it is impossible that a user performs an operation to turn on/off driving via, e.g., a switch disposed on an outer face of the casing because of its structure in which, e.g., an internal circuit is also sealed inside the casing. Therefore, capsule endoscopes including a switch inside their casings, the switch being turned on/off according to an external signal, have been proposed.
FIG. 1 illustrates a circuit diagram of a power source switch part of a capsule endoscope 110, which is disclosed in Japanese Patent Application Laid-Open Publication No. 2001-224553. In the capsule endoscope 110, power supply from a battery 119 to a main circuit is contactlessly switched on/off via a reed switch 112 whose contact point opens when the reed switch 112 is put in a magnetic field and a capacitor 112B. Also, for example, when the capsule endoscope 110 is being transported or is not used, the capsule endoscope 110 is stored in a packaging box or a storage case including a magnet, enabling a power source to be kept to be off